Up to now the following techniques for differentiating infection with the two viruses have been used: Virus isolation with typing, serological techniques (based on antibody competition or neutralization), or nucleic acid techniques (nucleic acid amplification or hybridization). Most of these techniques are laborious and require special competence.
Human T-lymphotropic virus type I (HTLV-I) and type II (HTLV-II) are widespread human retroviruses (a short review is given in ref. 6) (1, 2, 3, 20). HTLV-II has for several years been considered to be rare, but has recently proved to be a rather common infection among intravenous drug abusers primarily in the United States of America. The viruses cross-react serologically. It is therefore impossible to discriminate between an infection with one virus from an infection with the other with current antibody tests. It may prove clinically important to differentiate between infections with the two viruses. HTLV-I is associated with a type of leukemia (Adult T cell Leukemia; ATL) while HTLV-II has been observed in a few cases of hairy cell leukemia. There is a need for simple tests to differentiate between the two infections.
Even if the amino acid sequences of HTLV-I and HTLV-II proteins are similar there are several regions where they are markedly different. Our idea is to use synthetic peptides from such regions as antigens in antibody tests. We have found peptides with sequences which e.g. are suitable for solid phase immunoassays and which give a type-specific antibody reactivity. We have found techniques where we use them to discern infection with HTLV-I from infection with HTLV-II.